Field of the Invention
The present invention relates to an image forming apparatus and a print control method of the image forming apparatus, and particularly relates to a technique of reducing a consumption amount of a developing agent, such as a toner.
Description of the Related Art
In recent years, there is a demand for reducing a toner consumption amount in image forming apparatuses, and a number of methods have been proposed. According to a method disclosed in Japanese Patent Laid-Open No. 2004-299239, a technique of reducing a toner consumption amount by reducing exposure intensity in an image region having a certain area has been proposed. Furthermore, a phenomenon in which a developing toner amount in a rear end portion of a latent image is larger than a developing toner amount in a plane portion of the latent image, which is referred to as “sweeping”, occurs. To address this phenomenon, a technique of correcting the sweeping by performing a correction process on image data and controlling an exposure amount is proposed in Japanese Patent Laid-Open No. 2007-272153.
However, the method for controlling exposure intensity of individual pixels is also employed in various image processing techniques in addition to a technique of uniformizing a developing agent.
Examples of the techniques include a contour correction technique of adding subpixels in which exposure amounts thereof are suppressed to a step portion of rendering pixels so that an edge of a binary bit image is more smoothly printed.
The examples of the techniques further include a method for first adding pixels in which exposure amounts thereof are suppressed as pixels added to halftone dots with increase in color density and replacing the pixels in which the exposure amounts thereof are suppressed by pixels of full exposure amounts so that the number of steps in gradation in a certain area is increased.
In recent years, print output apparatuses have a plurality of techniques for enhancing high-quality printing, and the techniques are realized by controlling exposure intensity of pixels.
In a case where an image process of suppressing consumption of a developing agent is additionally performed on a system employing the image process described above, the image processes may interfere with each other and expected results may not be obtained in both of the image processes.
Although the same mechanism is used for the control of exposure amounts of the pixels to reduce a toner consumption amount and the control of exposure amounts of the pixels for image processes, such as contour correction, the exposure amounts of the individual pixels are controlled in accordance with different elements.
Here, a process of reducing exposure amounts performed to reduce a consumption amount of a developing agent and a process of reducing exposure amounts for image processes are to be appropriately adjusted.
To simultaneously realize these image processes and the process of reducing a consumption amount of a developing agent, such as a toner, a technique to be applied to individual pixels is to be determined.
However, since a combination of image processes is changed depending on an operation mode of the print output apparatus, it is difficult to make the determination.
For example, low-resolution rendering is performed so as to perform contour correction in a high-speed printing mode whereas resolution conversion is performed on high-resolution rendering data so that high-resolution rendering data has resolution of a printing mechanism in a high-quality printing mode.
Since different image data is used in different cases, it is difficult to make appropriate determinations for all results of combinations. The determination is more difficult in a case where image processes are successively performed on multivalued image data before a process of reducing a consumption amount of a developing agent is performed. In Japanese Patent Laid-Open No. 2009-198727, a determination is made by performing a binarization process on multivalued data between a registration process and another process so that complication of a determination circuit is avoided.
The present invention provides an image forming apparatus capable of reducing a consumption amount of a developing agent in image periphery portion and efficiently performing image contour correction.